1. Field of the Invention
The present invention relates to an ultraviolet detector which detects ultraviolet radiation incident thereon by converting them into an electric signal.
2. Related Background Art
An example of conventional ultraviolet detectors is disclosed in Japanese Utility model Publication No. 49-17184. This publication discloses an ultraviolet detector in which an anode and a cathode are disposed within a sealed vessel constituted by a glass envelope and a glass bottom plate welded to the bottom portion of the glass envelope.
Though the conventional ultraviolet detector mentioned above is an excellent detector which has a long life and can stably detect ultraviolet radiation, its characteristics may not be sufficient. Specifically, when used for a long period of time, its characteristics may deteriorate over time, thus lacking in stability.